CONVOLUTIONS OF THE BRAIN 



very marked feature, moreover, of the mammal's brain is the 

 development of regular fissures upon its surface, which fissures 

 are only absent from Ornithorhynchus, various small Eodents, 



B 



FIG. 49. Brain of Dog. A, ventral ; B, dorsal ; C, lateral aspect. B.ol, Olfactory lobe ; 

 Or.ce, cmra cerebri ; Fi.p, great longitudinal fissure ; Hit, HH 1 , lateral lobes of 

 cerebellum ; Hyp, hypophysis ; Med, spinal cord ; NH, medulla oblongata ; P, 

 pons Varolii ; VH, cerebral hemispheres ; Wu, middle lobe (vermis) of cerebellum ; 

 I-XII, cerebral nerves. (From Wiedersheim's Comparative Anatomy.) 



Bats, and Insectivores, among living mammals. It is some- 

 times, but erroneously, said that the more complicated the 

 fissures of the brain are, the higher in intelligence and " zoological 

 position " is the possessor of that brain. Instances can un- 

 doubtedly be quoted to support such a view ; but they are 



